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// ==================================================================
// >>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
// ------------------------------------------------------------------
// Copyright (c) 2006-2011 by Lattice Semiconductor Corporation
// ALL RIGHTS RESERVED
// ------------------------------------------------------------------
//
// IMPORTANT: THIS FILE IS AUTO-GENERATED BY THE LATTICEMICO SYSTEM.
//
// Permission:
//
// Lattice Semiconductor grants permission to use this code
// pursuant to the terms of the Lattice Semiconductor Corporation
// Open Source License Agreement.
//
// Disclaimer:
//
// Lattice Semiconductor provides no warranty regarding the use or
// functionality of this code. It is the user's responsibility to
// verify the user's design for consistency and functionality through
// the use of formal verification methods.
//
// --------------------------------------------------------------------
//
// Lattice Semiconductor Corporation
// 5555 NE Moore Court
// Hillsboro, OR 97214
// U.S.A
//
// TEL: 1-800-Lattice (USA and Canada)
// 503-286-8001 (other locations)
//
// web: http://www.latticesemi.com/
// email: techsupport@latticesemi.com
//
// --------------------------------------------------------------------
// FILE DETAILS
// Project : LatticeMico32
// File : lm32_debug.v
// Title : Hardware debug registers and associated logic.
// Dependencies : lm32_include.v
// Version : 6.1.17
// : Initial Release
// Version : 7.0SP2, 3.0
// : No Change
// Version : 3.1
// : No Change
// Version : 3.2
// : Fixed simulation bug which flares up when number of
// : watchpoints is zero.
// =============================================================================
`include "lm32_include.v"
`ifdef CFG_DEBUG_ENABLED
// States for single-step FSM
`define LM32_DEBUG_SS_STATE_RNG 2:0
`define LM32_DEBUG_SS_STATE_IDLE 3'b000
`define LM32_DEBUG_SS_STATE_WAIT_FOR_RET 3'b001
`define LM32_DEBUG_SS_STATE_EXECUTE_ONE_INSN 3'b010
`define LM32_DEBUG_SS_STATE_RAISE_BREAKPOINT 3'b011
`define LM32_DEBUG_SS_STATE_RESTART 3'b100
/////////////////////////////////////////////////////
// Module interface
/////////////////////////////////////////////////////
module lm32_debug (
// ----- Inputs -------
clk_i,
rst_i,
pc_x,
load_x,
store_x,
load_store_address_x,
csr_write_enable_x,
csr_write_data,
csr_x,
`ifdef CFG_HW_DEBUG_ENABLED
jtag_csr_write_enable,
jtag_csr_write_data,
jtag_csr,
`endif
`ifdef LM32_SINGLE_STEP_ENABLED
eret_q_x,
bret_q_x,
stall_x,
exception_x,
q_x,
`ifdef CFG_DCACHE_ENABLED
dcache_refill_request,
`endif
`endif
// ----- Outputs -------
`ifdef LM32_SINGLE_STEP_ENABLED
dc_ss,
`endif
dc_re,
bp_match,
wp_match
);
/////////////////////////////////////////////////////
// Parameters
/////////////////////////////////////////////////////
parameter breakpoints = 0; // Number of breakpoint CSRs
parameter watchpoints = 0; // Number of watchpoint CSRs
/////////////////////////////////////////////////////
// Inputs
/////////////////////////////////////////////////////
input clk_i; // Clock
input rst_i; // Reset
input [`LM32_PC_RNG] pc_x; // X stage PC
input load_x; // Load instruction in X stage
input store_x; // Store instruction in X stage
input [`LM32_WORD_RNG] load_store_address_x; // Load or store effective address
input csr_write_enable_x; // wcsr instruction in X stage
input [`LM32_WORD_RNG] csr_write_data; // Data to write to CSR
input [`LM32_CSR_RNG] csr_x; // Which CSR to write
`ifdef CFG_HW_DEBUG_ENABLED
input jtag_csr_write_enable; // JTAG interface CSR write enable
input [`LM32_WORD_RNG] jtag_csr_write_data; // Data to write to CSR
input [`LM32_CSR_RNG] jtag_csr; // Which CSR to write
`endif
`ifdef LM32_SINGLE_STEP_ENABLED
input eret_q_x; // eret instruction in X stage
input bret_q_x; // bret instruction in X stage
input stall_x; // Instruction in X stage is stalled
input exception_x; // An exception has occured in X stage
input q_x; // Indicates the instruction in the X stage is qualified
`ifdef CFG_DCACHE_ENABLED
input dcache_refill_request; // Indicates data cache wants to be refilled
`endif
`endif
/////////////////////////////////////////////////////
// Outputs
/////////////////////////////////////////////////////
`ifdef LM32_SINGLE_STEP_ENABLED
output dc_ss; // Single-step enable
reg dc_ss;
`endif
output dc_re; // Remap exceptions
reg dc_re;
output bp_match; // Indicates a breakpoint has matched
wire bp_match;
output wp_match; // Indicates a watchpoint has matched
wire wp_match;
/////////////////////////////////////////////////////
// Internal nets and registers
/////////////////////////////////////////////////////
genvar i; // Loop index for generate statements
// Debug CSRs
reg [`LM32_PC_RNG] bp_a[0:breakpoints-1]; // Instruction breakpoint address
reg bp_e[0:breakpoints-1]; // Instruction breakpoint enable
wire [0:breakpoints-1]bp_match_n; // Indicates if a h/w instruction breakpoint matched
reg [`LM32_WPC_C_RNG] wpc_c[0:watchpoints-1]; // Watchpoint enable
reg [`LM32_WORD_RNG] wp[0:watchpoints-1]; // Watchpoint address
wire [0:watchpoints-1]wp_match_n; // Indicates if a h/w data watchpoint matched
wire debug_csr_write_enable; // Debug CSR write enable (from either a wcsr instruction of external debugger)
wire [`LM32_WORD_RNG] debug_csr_write_data; // Data to write to debug CSR
wire [`LM32_CSR_RNG] debug_csr; // Debug CSR to write to
`ifdef LM32_SINGLE_STEP_ENABLED
// FIXME: Declaring this as a reg causes ModelSim 6.1.15b to crash, so use integer for now
//reg [`LM32_DEBUG_SS_STATE_RNG] state; // State of single-step FSM
integer state; // State of single-step FSM
`endif
/////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////
/////////////////////////////////////////////////////
// Combinational Logic
/////////////////////////////////////////////////////
// Check for breakpoints
generate
for (i = 0; i < breakpoints; i = i + 1)
begin : bp_comb
assign bp_match_n[i] = ((bp_a[i] == pc_x) && (bp_e[i] == `TRUE));
end
endgenerate
generate
`ifdef LM32_SINGLE_STEP_ENABLED
if (breakpoints > 0)
assign bp_match = (|bp_match_n) || (state == `LM32_DEBUG_SS_STATE_RAISE_BREAKPOINT);
else
assign bp_match = state == `LM32_DEBUG_SS_STATE_RAISE_BREAKPOINT;
`else
if (breakpoints > 0)
assign bp_match = |bp_match_n;
else
assign bp_match = `FALSE;
`endif
endgenerate
// Check for watchpoints
generate
for (i = 0; i < watchpoints; i = i + 1)
begin : wp_comb
assign wp_match_n[i] = (wp[i] == load_store_address_x) && ((load_x & wpc_c[i][0]) | (store_x & wpc_c[i][1]));
end
endgenerate
generate
if (watchpoints > 0)
assign wp_match = |wp_match_n;
else
assign wp_match = `FALSE;
endgenerate
`ifdef CFG_HW_DEBUG_ENABLED
// Multiplex between wcsr instruction writes and debugger writes to the debug CSRs
assign debug_csr_write_enable = (csr_write_enable_x == `TRUE) || (jtag_csr_write_enable == `TRUE);
assign debug_csr_write_data = jtag_csr_write_enable == `TRUE ? jtag_csr_write_data : csr_write_data;
assign debug_csr = jtag_csr_write_enable == `TRUE ? jtag_csr : csr_x;
`else
assign debug_csr_write_enable = csr_write_enable_x;
assign debug_csr_write_data = csr_write_data;
assign debug_csr = csr_x;
`endif
/////////////////////////////////////////////////////
// Sequential Logic
/////////////////////////////////////////////////////
// Breakpoint address and enable CSRs
generate
for (i = 0; i < breakpoints; i = i + 1)
begin : bp_seq
always @(posedge clk_i `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
begin
bp_a[i] <= {`LM32_PC_WIDTH{1'bx}};
bp_e[i] <= `FALSE;
end
else
begin
if ((debug_csr_write_enable == `TRUE) && (debug_csr == `LM32_CSR_BP0 + i))
begin
bp_a[i] <= debug_csr_write_data[`LM32_PC_RNG];
bp_e[i] <= debug_csr_write_data[0];
end
end
end
end
endgenerate
// Watchpoint address and control flags CSRs
generate
for (i = 0; i < watchpoints; i = i + 1)
begin : wp_seq
always @(posedge clk_i `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
begin
wp[i] <= {`LM32_WORD_WIDTH{1'bx}};
wpc_c[i] <= `LM32_WPC_C_DISABLED;
end
else
begin
if (debug_csr_write_enable == `TRUE)
begin
if (debug_csr == `LM32_CSR_DC)
wpc_c[i] <= debug_csr_write_data[3+i*2:2+i*2];
if (debug_csr == `LM32_CSR_WP0 + i)
wp[i] <= debug_csr_write_data;
end
end
end
end
endgenerate
// Remap exceptions control bit
always @(posedge clk_i `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
dc_re <= `FALSE;
else
begin
if ((debug_csr_write_enable == `TRUE) && (debug_csr == `LM32_CSR_DC))
dc_re <= debug_csr_write_data[1];
end
end
`ifdef LM32_SINGLE_STEP_ENABLED
// Single-step control flag
always @(posedge clk_i `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
begin
state <= `LM32_DEBUG_SS_STATE_IDLE;
dc_ss <= `FALSE;
end
else
begin
if ((debug_csr_write_enable == `TRUE) && (debug_csr == `LM32_CSR_DC))
begin
dc_ss <= debug_csr_write_data[0];
if (debug_csr_write_data[0] == `FALSE)
state <= `LM32_DEBUG_SS_STATE_IDLE;
else
state <= `LM32_DEBUG_SS_STATE_WAIT_FOR_RET;
end
case (state)
`LM32_DEBUG_SS_STATE_WAIT_FOR_RET:
begin
// Wait for eret or bret instruction to be executed
if ( ( (eret_q_x == `TRUE)
|| (bret_q_x == `TRUE)
)
&& (stall_x == `FALSE)
)
state <= `LM32_DEBUG_SS_STATE_EXECUTE_ONE_INSN;
end
`LM32_DEBUG_SS_STATE_EXECUTE_ONE_INSN:
begin
// Wait for an instruction to be executed
if ((q_x == `TRUE) && (stall_x == `FALSE))
state <= `LM32_DEBUG_SS_STATE_RAISE_BREAKPOINT;
end
`LM32_DEBUG_SS_STATE_RAISE_BREAKPOINT:
begin
// Wait for exception to be raised
`ifdef CFG_DCACHE_ENABLED
if (dcache_refill_request == `TRUE)
state <= `LM32_DEBUG_SS_STATE_EXECUTE_ONE_INSN;
else
`endif
if ((exception_x == `TRUE) && (q_x == `TRUE) && (stall_x == `FALSE))
begin
dc_ss <= `FALSE;
state <= `LM32_DEBUG_SS_STATE_RESTART;
end
end
`LM32_DEBUG_SS_STATE_RESTART:
begin
// Watch to see if stepped instruction is restarted due to a cache miss
`ifdef CFG_DCACHE_ENABLED
if (dcache_refill_request == `TRUE)
state <= `LM32_DEBUG_SS_STATE_EXECUTE_ONE_INSN;
else
`endif
state <= `LM32_DEBUG_SS_STATE_IDLE;
end
endcase
end
end
`endif
endmodule
`endif